The present invention relates to a diagnostic apparatus and method for evaluating brain condition, and in particular, to a method combining quantitative data from a magnetic resonance imaging (MRI) system for improved characterization of brain condition and in particular brain trauma or injury.
Brain injury and in particular mild traumatic brain injury (mTBI) can be structurally subtle and thus largely invisible to standard qualitative imaging techniques. For this reason, standard and widely used diagnostic tools such as CT and MRI imaging are largely unsuccessful in characterizing brain abnormalities associated with such injury.
Quantitative MRI imaging, such as diffusion-weighted imaging (DWI), holds more promise in characterizing brain trauma. The measurement of water diffusion in brain tissue can indicate, for example, swelling (edema) or scarring in the brain tissue associated with trauma. Changes in anisotropy of diffusion of water in brain tissue can also reveal changes in the organizational structure of the brain, for example, caused by axonal injury (e.g., shearing). Such injury can disrupt the path of water diffusion associated with white matter neural tracts. Such neural tracts can be visualized by Diffusion Tensor Imaging (DTI), for example. Fractional Anisotropy (FA) derived from DTI has been used to assess changes in brain microstructure associated with axonal injury.
Different types of brain injury are highly variable in terms of severity, brain location, and type of pathology (e.g., axonal shearing, hemorrhage, edema, glial death, etc.) making it difficult to accurately assess brain trauma using these quantitative measures. For example, brain trauma can cause either increased fractional anisotropy or decreased fractional anisotropy in different cases. Variations in patient history and characteristics such as age can make it challenging to assess brain trauma from the quantitative information provided by techniques such as fractional anisotropy.